As the display technology continues to progress, presentation of stereoscopic images has gradually evolved from stereoscopic display devices cooperating with special glasses worn by users to autostereoscopic display devices that no longer require the special glasses. With a stereoscopic display device that requires special glasses, a viewer can observe stereoscopic images on the basis of two two-dimensional images respectively corresponding to left and right eyes. However, for an autostereoscopic display device that requires no special glasses, various factors must be taken into consideration, such as head movements of viewers, change in positions of viewers, and different viewing angles of multiple viewers viewing simultaneously. Therefore, multiple two-dimensional images need to be filmed from different angles (e.g., nine angles) to compose a stereoscopic image.
To alleviate pseudoscopy resulted by change in positions, high-level autostereoscopic display devices need numerous multi-angle images (e.g., 36 or 72 angles) to compose stereoscopic images. However, capturing images using video cameras in such a greater number is impractical. Thus, in real situations, one or two video cameras are utilized for capturing (original) images, which are coordinated with corresponding disparity maps (storing distances between respective objects in a two-dimensional image and a reference plane). Images projected from different angles and corresponding disparity maps are then calculated to compose stereoscopic images with wide viewing angles.
When calculating the projected images of the various viewing angles, a part that is occluded by the foreground in an original image may be revealed when viewing from different angles. A hole is formed as no sufficient information is available for filling the disoccluded part. To solve this problem, a reasonable value should be first filled in the hole in the disparity map, so that appropriate image data can be searched for or calculated to fill the hole in the image.
In the prior art, a minimum disparity value of neighboring regions of the hole in the disparity map, or a minimum disparity value of the whole disparity map is found for filling the hole. However, both of the two approaches above encounter the following two issues. One issue is that no reasonable value can be found from the neighboring regions to fill the hole when the hole is surrounded by the foreground. The other issue is that filling the hole by a minimum disparity value of the whole disparity map is unreasonable in a multi-layer scene.